In some of the conventional fluid spraying devices of the type having a spraying nozzle, a high speed turning motion of a fluid or fluids caused by the device per se is utilized for forming a dispersion stream of the fluid or fluids. However, in the above-mentioned type of the conventional spraying device, a defect is encountered in that when the spraying nozzle of the device is located in a gaseous environment so that more than one liquid is concurrently dispersed from the spraying nozzle into the gaseous environment, complete atomizing and mixing of the liquids is not achieved. On the other hand, when the spraying nozzle of the conventional spraying device is located in a liquid so that a gaseous fluid or fluids are dispersed from the nozzle into the surrounding liquid, a defect is encountered in that complete separation of the gaseous fluid into fine bubbles is not attained.
The above-mentioned defects encountered with the conventional spraying device are caused because, in the structure of the conventional spraying device, effective use of the hydrodynamic low pressure zone cannot be made. That is to say, although hydrodynamic low pressure zones are created in a region in which the high speed turning motion of fluids is caused, as well as in the other region in which the fluids are dispersed from the spraying device, any fluid surrounding the device is easily dragged into the created hydrodynamic low pressure zones. Therefore, the hydrodynamic low pressure zones are not able to contribute to the high speed dispersion of the fluids.